Field of the Invention
The invention generally relates to configurations of periodic update timers, and more particularly, to a method to configure periodic update timers for Machine Type Communication (MTC) devices.
Description of the Related Art
For a long time, various machines have been provided to make our lives more convenient in every way. Nowadays, machines are generally equipped with computing processors and software to accommodate us with more intelligence-based services. With the advancement of wireless communications, Machine Type Communication (MTC) technology has been developed to enable wireless communications between remote machines for exchanging information and operating without human interaction. Especially for critical public infrastructure, such as water treatment facilities or bridges, MTC sensors may be employed to monitor the operation statuses of facilities and to report measurement results back to control centers via a wireless communication technology, such as the Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, High Speed Packet Access (HSPA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced technology, Time-Division LTE (TD-LTE) technology, etc.
According to the 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 23.887, v12.0.0, a service network may configure low-mobility and/or low-power MTC devices to deactivate their periodic update timers for saving power. The periodic update timers include the periodic Location Update (LU) timer T3212, the periodic Routing Area Update (RAU) timer T3312, and the periodic Tracking Area Update (TAU) timer T3412.
According to the 3GPP TS 24.008, v12.0.0 and TS24.304, v12.0.0, a service network may assign new values for the periodic update timers to MTC devices through system information broadcasts or LU procedures. However, if certain MTC devices were configured by the service network to deactivate the periodic LU timer T3212 through previously performed LU procedures (by assigning a zero value for the periodic LU timer T3212), those MTC devices will deliberately ignore any new values of the periodic LU timer T3212 contained in later system information broadcasts. As a result, when the service network detects that certain MTC devices haven't performed LU procedures over a period of time, it cannot identify whether the MTC devices are malfunctioning or whether they have applied the zero value for the periodic LU timer T3212. That is, in the conventional design, in-synchronization between the service network and the MTC devices may occur regarding the values in use for the periodic LU timer T3212.
In addition, according to the 3GPP TS 24.008, v12.0.0 and TS24.304, v12.0.0, if the user or the service network wishes to reactivate the periodic LU timer T3212, the periodic RAU timer T3312, or the periodic TAU timer T3412 in the MTC devices, the MTC devices will be required to detach from the service network first, and then re-attach to the service network to obtain a new value for reactivating the periodic LU timer T3212, the periodic RAU timer T3312, or the periodic TAU timer T3412. However, the detachment and re-attachment processes involve a great number of signaling messages to be exchanged between the MTC devices and the service network, which inevitably causes serious interruptions to the ongoing wireless communications therebetween.